Purple Fluorite Cubic Cluster — Ex-Gundersen Geology Collection

Cabinet-scale fluorite specimen with deeply saturated violet-purple cubic crystals in interpenetrant and stepped parallel growth, set on a contrasting matrix of drusy quartz with secondary fluorite and dark accessory mineral inclusions. The display face presents a tight cascade of sharp, glassy cubes ranging to over 2" across, with the layered notch-and-step edges characteristic of the larger fluorites recovered from the Illinois-Kentucky Fluorspar District. Color reads as near-monocolor deep grape-purple under standard light and gains considerable depth under backlighting. Morphology, color saturation, and matrix are most consistent with Cave-in-Rock District material, Hardin County, Illinois, though the lot is offered without formal locality documentation and bidders are encouraged to assess independently. Twelve pounds and over nine inches across the long axis, this is a display-authority piece rather than a study specimen.

From the personal collection of Dr. James N. Gundersen (1925–2008), Professor of Geology at Wichita State University and the recognized academic authority on the mineralogical characterization of Plains catlinite. Gundersen's 1991 National Park Service monograph on Pipestone National Monument remains the standard reference work in the field. His personal catlinite reference collection was donated to the monument in his lifetime; his broader mineral collection retired with him to Las Cruces, New Mexico, and is now being released from the family estate. Original shipping carton bearing the Pipestone County Historical Society / Wichita State University Department of Geology routing accompanies the lot as a provenance artifact. The closure of all major Illinois fluorspar operations — Minerva, Annabel Lee, Denton, Rosiclare — has removed Cave-in-Rock specimens from new production for nearly three decades.

CONDITION

Very Good. Crystal faces on the display front are bright, sharp, and lustrous with no significant chipping to primary cubes. Minor contact points and shallow surface pits visible at crystal junctions and along matrix edges; stepped cleavage planes on several cubes are natural to the growth habit and not damage. No repairs or restoration apparent.

DIMENSIONS / SPECIFICATIONS

• Overall: 5 1/4" x 9 1/4" x 6 1/2"
• Weight: 5500 grams
• Species: Fluorite (primary), Quartz (matrix)
• Crystal habit: Cubic with stepped/parallel growth
• Color: Deep violet to blackberry purple
• Provenance: Ex. Dr. James N. Gundersen Collection, Wichita State University Geology Department
• Original shipping carton from Pipestone County Historical Society to Wichita State accompanies the lot
• Campbell's Soup Can (4" H) Shown for Scale